This invention relates to a two-cycle engine oil composition, and more specifically to a two-cycle engine oil composition permitting a reduction of the smoke concentration in the exhaust gas and removal of disagreeable or irritating odor to give pleasant or aromatic smell.
Two-cycle engines employed in motor cycles, chain saws and the like are operated by mixing gasoline as a fuel and two-cycle engine oil at prescribed proportions. The separate oiling (or lubricating) system has been dominantly adopted for the two-cycle engines in motor cycles and the like with a view toward achieving a reduction of the smoke concentration in the exhaust gas and an improvement in the cleaness of the exhaust gas. However, no satisfactory improvement has been reported with respect to two-cycle engine oils.
Two-cycle engine oil compositions are required to have such properties as (1) good detergency, (2) low smoke concentration in the exhaust gas, (3) exhaust gas free of disagreeable and/or irritating odors, (4) excellent anti-seizure property and the like.
Especially, the properties (2) and (3) have been attracting attention in recent years from the viewpoints of prevention of public pollution and protection of our living environments from contamination. Researches have been made with a view toward improving such properties, leading to some proposals on improved two-cycle engine oil compositions (see, Japanese Patent Publication Nos. 24521/1976; 24522/1976; 20467/1972; 34317/1982; etc.).
The above-proposed two-cycle engine oil compositions can certainly reduce the smoke concentration in the exhaust gas but cannot render the exhaust gas free of disagreeable oder. There is thus a standing demand for the development of an excellent two-cycle engine oil composition which is capable of reducing the smoke concentration and removing such disagreeable odor.